A wide variety of soap bar compositions and manufacturing processes are known in the art. Commonly, soap bar compositions for toiletry purposes are milled soaps of low moisture content (from about 5% to about 18% water) based on a mixture of tallow and coconut oil feedstocks. Bars having milled soap characteristics can also be prepared from soap of a high moisture content, as described for example in U.S. Pat. Nos. 2,686,761 and 2,970,116 by mechanically working the soap at a temperature of from about 80.degree. F. to 125.degree. F. and by using an appropriate fat feedstock. Such a process has two main advantages; firstly, it is relatively energy-efficient in that less drying of the neat-kettle soap is required; and secondly, it produces soap bars having desirable translucency or transparency as a result of beta-phase soap formation.
From the consumer acceptance viewpoint, of course, the skin conditioning performance and cosmetic attributes of a toilet bar composition are highly important and there is a continuing need to improve these aspects of performance. One particular area where conventional soap bar formulations have been deficient is in cleansing of skin of a typically oil nature, many people within this category finding that conventional products fail to deal with the oiliness problem with the result that the skin develops an excessively shiny appearance. This in turn is viewed as evidence of poor skin condition.
Although a number of additive materials have been identified which can enhance oily skin condition, a major constraint on the use of such materials in beta-phase transparent or translucent bars is that there is no impairment of the physical, performance and aesthetic characteristics of the bar.
It has now been discovered that the addition of certain smectite-type clay materials to toilet bars of the transparent or translucent variety not only has a beneficial effect on oily (or oily/dry combination) skin condition but that the improvement is achieved without detriment to toilet bar performance (lathering, mildness, smear etc), physical characteristics (beta-phase formation) and above all, bar aesthetics (transparency or transluency).
Although the use of clay materials in detergent bars is already known on the art(eg GB-A-2083490, GB-A-2083491 and GB-A-2127426), there has apparently been no previous disclosure of transparent or translucent bars for personal cleansing containing the specified clay materials for improving oily skin condition.